Arizona electric companies again on Wednesday called upon customers to reduce energy use late in the day to reduce the potential for blackouts, and the call became more urgent when a wildfire near Roosevelt Lake disabled a power line.
Arizona Public Service Co. and Tucson Electric Power Co. had asked customers to conserve from 3 p.m. to 8 p.m. Tuesday and repeated the call Wednesday. Salt River Project joined them Wednesday because of the wildfire damage.
Weather forecasts show some parts of the Southwest cooling a few degrees Thursday. That should eliminate the need for the conservation requests in Arizona, although officials said they are making decisions day to day.
During the afternoon and evening hours, customers were encouraged to turn thermostats no lower than 78 degrees, turn off unused lights and delay using major appliances including pool pumps until later.
SRP had not joined other utilities Tuesday asking for conservation, but that changed when a transmission line that imports power to the Phoenix area was taken out of service by the Salt Fire in the Tonto National Forest.
SRP spokesman Scott Harelson said smoke from the wildfire caused the line to get cut off. Dense wildfire smoke can cause power lines to arc. SRP was able to get the transmission line back in service Wednesday evening, he said.
“That’s good news, but there is still a lot of smoke from this fire so the line could easily trip again,” Harelson said.
The power line that was affected brings power from the Coronado and Springerville coal plants in northeastern Arizona to SRP customers in the Phoenix area.
SRP said the rest of its system was running normally, but that rolling blackouts could be needed to meet electricity demand during the scorching afternoon.
SRP asked customers to conserve until 9 p.m., an hour later than APS.
Rolling blackouts, which SRP refers to as “rotating outages,” are used to cut off power to thousands of customers at a time for 20 to 30 minutes, then restore their power and shut off another block of customers.
They are used to prevent broader, uncontrolled outages that can result when demand from customers is greater than power on the grid from operating power plants.
The unusual call for customer conservation in Arizona first came Tuesday as California utilities asked for the same.
California utilities warned millions of people this week they face potential blackouts because electricity demand is so high.
California residents heeded the call Tuesday, cutting back use enough to avoid rolling blackouts like the state saw Friday and Saturday.
Blackouts caused by storms or accidents are common. And California has even forced blackouts during high winds to prevent sparking lines from igniting wildfires. But outages caused by utilities not having enough energy to supply customers are rare.
The supply-induced outages Friday and Saturday in California were the first since the California energy crisis in 2000 and 2001.
SRP had to use rolling blackouts for about 65,000 customers in February 2011 when a hard freeze caused problems across the West, including at multiple power plants the company runs across the state.
The situation was less dire in Arizona this week. But utilities here said Tuesday that if they were to lose a major power plant or transmission line, there just wasn’t enough power available on the market to make it up, so they asked customers to cut back.
Arizona also saw a “meaningful” reduction in power use after APS and Tucson Electric Power Co. used social media and news organizations to ask customers to cut their usage Tuesday.
“I can say it definitely worked,” APS spokesman Jim McDonald said. “We quickly saw a change in how much energy customers were using in the 3-8 p.m window, and it made a meaningful difference.”
APS declined to share figures on how many megawatts of electricity demand were shed in those hours as customers were asked to conserve.
Tuesday was the first time since July 2004 that APS made such a request, and it was only done that year because a critical piece of infrastructure exploded after being damaged the previous month in an outage caused by a blue heron’s droppings on electrical equipment.
TEP also renewed its call for voluntary conservation on Wednesday.
“While TEP is not selling energy to California, these conditions have limited supplies and increased prices on the wholesale energy market in both California and Arizona,” the company said in a news release. “TEP and other Arizona utilities rely on that market to supplement the resources we’ve secured to serve our own customers’ energy needs.”
McDonald said APS did sell power to California on Tuesday, as well as Nevada, but only when the utility was able to do that without affecting Arizona customers.
He said all utilities are obligated to provide such assistance by national grid regulators.
“For APS, this means we have that obligation when California, Nevada and New Mexico utilities have that need, and likewise that if we were in…
Read More: APS, SRP, TEP ask customers to cut power use